Abstract
The Carpathian mountain ecosystems have been changed under anthropogenic pressure during last decades. The different types of anthropogenic pressure affect the ecosystem characteristics and functioning. The species composition, species richness and ecological indicator values of 12 ecological factors were compared among 14 habitats: natural, semi-natural, degraded and ruderal ecosystems in different altitude zones. The results show that anthropogenic pressure and altitude gradient influence indices of edaphic and climate conditions. The anthropogenic pressure also affects biodiversity: the highest species richness and Shannon-Wiener index are observed in habitats with ‘intermediate’ disturbances level, while high level of disturbances cause decrease in bio-diversity. The disturbances cause the ecosystem to become susceptible to invasion of alien species, while native species, especially rare, become vulnerable and can disappear.